Gabbert has a torn labrum in his left shoulder, ESPN.com's Ed Werder reported Tuesday.
Jacksonville coach Mike Mularkey said Monday before Gabbert's MRI exam "There is a good chance he will be able to play this week. We will see how it is on Wednesday. Chad (Henne) will be prepared to go, as he is every week, not different. We are thinking a lot of it will be up to Blaine to see how his shoulder feels. "
Gabbert, a first-round pick in 2011, completed 8 of 12 passes in Sunday's overtime loss at Oakland. He was knocked out of the game in favor of Chad Henne, and the offense, ranked 32nd in the NFL, remained stagnant.
Mularkey said the team's running backs share the blame for some of the lapses in protection. When the team practiced Saturday morning at San Jose State's stadium, he even talked to the backs about protection.
"I said when those guys come off the edge, we've got to step up and block them as quickly as we can," Mularkey said. "Don't give them a head of steam to where they can push you back in the quarterback. We didn't get that done. Obviously, that's something I've got to do more. We've got to practice it more or whatever we've got to do."
Gabbert's availability is uncertain for Sunday's game until he meets with renowned surgeon James Andrews.
-- The Sports Xchange